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DataLogging ?

Greg:

When I ran a test on the method I used with the low-level File I/O
functions to verify my reply to the original post, reading the datalog
file failed unless I put the U16 in the time stamp cluster first.
I just ran a test on the database method you recommend and also on the
low-level method (using the exact same datalog file I used yesterday)
and it seems the time-stamp cluster is in the opposite order and indeed
the U32 comes first, exactly as described in the manual. Any ideas on
why the read datalog would have failed? Did I just do something stupid?

My apologies again to the group. The cluster for the time stamp is:

element 0 = U32
element 1 = U16


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Message 10 of 13
(940 Views)
LabView Users:
Recently I was dealing with similar issues of storing complex data structures
such as clusters in a file. There is a VI in the Advanced/ Data Manipulation
palate called Flatten Data that has converts complex data structures into a
formated string. In the same palete there is a complementary VI which Unflattens
the data. Once the structure is converted in to a string it can easily be stored
using the basic file I/O VI's.

Brian Wells
Spcae Power Institute

Greg McKaskle wrote:

> > Does anyone know of any more information on how to use and get back
> > the information when you try to use Datalogging. I created a file
> > using datalogging for a sub vi and using the manual I tried to create
> > the program that would read the data back fo
r me but I couldn't get
> > anything to work. I also couldn't find the icon they talked about in
> > any of the menu's. I want to get the data in this file because it may
> > help me debug a problem I'm having. Thanks for any more information
> > you can give.
> >
>
> The other responses describe how to do this using the lowest level file I/O
> icons. The other way is to drop the same subVI icon on the diagram, popup
> on it and choose Enable Database Access or something very similar. This will
> put what we refer to as a datalogging halo around the icon that allows you
> to specify which datalog record you want back, and you can also wire to any
> of the icon terminals to read back specific control/indicator values as well
> as to the timestamp and other values.
>
> Greg McKaskle
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Message 12 of 13
(579 Views)
LabView Users:
Recently I was dealing with similar issues of storing complex data structures
such as clusters in a file. There is a VI in the Advanced/ Data Manipulation
palate called Flatten Data that has converts complex data structures into a
formated string. In the same palete there is a complementary VI which Unflattens
the data. Once the structure is converted in to a string it can easily be stored
using the basic file I/O VI's.

Brian Wells
Spcae Power Institute

Greg McKaskle wrote:

> > Does anyone know of any more information on how to use and get back
> > the information when you try to use Datalogging. I created a file
> > using datalogging for a sub vi and using the manual I tried to create
> > the program that would read the data back fo
r me but I couldn't get
> > anything to work. I also couldn't find the icon they talked about in
> > any of the menu's. I want to get the data in this file because it may
> > help me debug a problem I'm having. Thanks for any more information
> > you can give.
> >
>
> The other responses describe how to do this using the lowest level file I/O
> icons. The other way is to drop the same subVI icon on the diagram, popup
> on it and choose Enable Database Access or something very similar. This will
> put what we refer to as a datalogging halo around the icon that allows you
> to specify which datalog record you want back, and you can also wire to any
> of the icon terminals to read back specific control/indicator values as well
> as to the timestamp and other values.
>
> Greg McKaskle
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Message 13 of 13
(579 Views)